Korean Journal of Chemical Engineering, Vol.39, No.11, 2991-3002, November, 2022
Flow behavior of gadolinium doped ceria under different polymeric and hydrodynamic environment for tape casting application
The present investigation consists of a comprehensive analysis of the rheological properties of tape casting slurry and optimization of its composition through rheological results. Formulation of slurry consists of gadolinium doped ceria (GDC) powder, solvent (ethanol and toluene), dispersant (menhaden fish oil), plasticizer (benzyl butyl phthalate160 and polyethylene glycol 8000), and binder (polyvinyl butyral 98). The slurry exhibits pseudoplastic behavior, which is drastically affected by a minute change in powder content. These changes in the flow properties were traced in terms of shear dependence (m) and fractal dimension (df) of aggregates, along with the trend of growth in aggregate size (R) and its volume fraction (Φa) in the presence of different additives. These results suggest that the GDC particles tend to form large, rigid aggregates, which show appearance of yield stress even at Φ>0.06. Furthermore, the addition of polymeric chains in the form of additives causes the steric stabilization of aggregates and formation of their 3-D network structure, which suppresses the sedimentation velocity to zero and provides crack-free and homogeneous green tape.